Arboreus and his crew of eco-warriors plot to destroy the Langley Falls Shopping Mall in "Finances With Wolves". He believes himself to be a tree trapped in a man's body. Hayley runs into the group while performing her own sabotage on construction equipment used for the mall's expansion. Arboreus takes things even farther than Hayley, intended when he plants bombs in the mall and detonates them, causing Hayley to turn against him and his friends. She kicks the pot he was in and breaks it, leaving him and his eco-warriors to be arrested.
Arboreus and his gang have cameos in "100 A.D.". In addition, Arboreus's gang members have had various cameos such as in "My Morning Straitjacket" and in "Phantom of the Telethon".
Arboreus is voiced by David Herman.